1. Field of the Invention
The present invention relates to a roll-up table top assembly, more particularly to a roll-up table top assembly which includes coupling units that render the table top assembly easier to manufacture and assemble and that imparts enhanced rigidity to the table top assembly when the table top assembly is unrolled.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional roll-up table top assembly 1 is shown to include a plurality of parallel slats 11, three connecting straps 12 and a plurality of mounting plates 13. The slats 11 are formed integrally from plastic and have a top wall 111, a surrounding wall 112 extending downwardly from the periphery of the top wall 111, and three longitudinally extending reinforcing ribs 113 connected to the top wall 111 and the surrounding wall 112. Each of the slats 11 has three spaced positioning units 117, each of which includes four downwardly extending positioning tubes 114 which are arranged in a rectangular configuration and teeth 116 formed between adjacent pairs of the positioning tubes 114. Two adjacent ones of the positioning tubes 114 of each of the positioning units 117 are formed on an outer one of the reinforcing ribs 113 that is disposed adjacent to one of the longitudinal sides of the surrounding wall 112. The other two adjacent ones of the positioning tubes 114 are formed on an opposite outer one of the reinforcing ribs 113 that is disposed adjacent to the other one of the longitudinal sides of the surrounding wall 112. Each of the positioning tubes 114 confines an axial positioning hole 115. The connecting straps 12 are made of a flexible material. Each of the connecting straps 12 extends transversely across bottom sides of the parallel slats 11, and is disposed between the positioning tubes 114 of corresponding positioning units 117 of the parallel slats 11. Each of the mounting plates 13 is rectangular in shape and is formed with four positioning posts 132 at four corners thereof. The mounting plates 13 are formed with teeth 133 and are disposed under the connecting straps 12. The posts 132 of each of the mounting plates 13 extend into the axial positioning holes 115 of the positioning tubes 114 of a corresponding one of the positioning units 117 so that the connecting straps 12 are retained between the teeth 133 of the mounting plates 13 and the teeth 116 of the positioning unit 117 in order to mount the slats 11 on the connecting straps 12.
To assemble the table top assembly 1, the slats 11 are disposed side by side, and the connecting straps 12 are disposed at the bottom sides of the slats 11 so that each of the connecting straps 12 extends transversely relative to the slats 11 between the positioning tubes 114 of the corresponding positioning units 117. Glue is applied to the posts 132 of each of the mounting plates 13, and the mounting plates 13 are then pressed onto the positioning units 117 to engage the posts 132 with the corresponding positioning tubes 114. The connecting straps 12 are thus sandwiched and retained between the mounting plates 13 and the positioning units 117 for connecting the slats 11 side by side to each other. Assembly of the table top assembly 1 is thus completed. The table top assembly 1 can either be unrolled and supported on a leg assembly 14 for placing objects thereon, as shown in FIG. 3, or rolled-up for storage or transport.
Although the table top assembly 1 can be conveniently rolled-up and unrolled for use, the table top assembly 1 is still not satisfactory for the following reasons:
1. Since the slats 11 of the table top assembly 1 are connected to one another by means of the flexible connecting straps 12, a localized indented part might be formed on the table top assembly 1 when pressure is applied to that part. In other words, the aforementioned table top assembly 1 does not posses sufficient rigidity. PA0 2. The slats 11 are mounted on the connecting straps 12 by means of a plurality of mounting plates 13 that have positioning posts 132 which extend into the positioning tubes 114 of the slats 11. The slats 11, the connecting straps 12 and the mounting plates 13 should be manufactured separately. Therefore, the manufacturing of the table top assembly 1 is complicated, and the assembly thereof is relatively troublesome. PA0 3. Since the slats 11 are connected by means of the connecting straps 12, the distance between adjacent pairs of the slats 11 cannot be controlled precisely. As such, the slats 11 tend to have a somewhat disorderly arrangement.